In a small-sized and thin portable electronic device such as a mobile phone, an area on which a semiconductor device is mounted is narrow, and its height is low. A thin semiconductor device such as a double-sided mounting semiconductor device having semiconductor chips mounted on both surfaces of a substrate has been required. The thin semiconductor device is manufactured in the following manner, for example. First, a wiring layer is formed on a predetermined supporting substrate, and then a semiconductor chip is mounted on a front surface of the wiring layer. The semiconductor chip is resin-sealed to obtain a resin-sealed body, and then the supporting substrate is removed, and thereby the thin semiconductor device is manufactured. The double-sided mounting semiconductor device is manufactured by mounting a semiconductor chip also on a rear surface of the wiring layer.
In a manufacturing process of the above-described semiconductor device, a removing process of the supporting substrate is important. The removing process of the supporting substrate is required to enable repeated use of the supporting substrate and to simply remove the supporting substrate for a short time without causing any trouble in the semiconductor chip or the wiring layer. With respect to such a point, there has been proposed a method in which a separation layer that is formed between a supporting substrate and a wiring layer and is made of a thermoplastic resin and so on is sheared, and thereby a circuit structure body having the wiring layer, a semiconductor chip, and a sealing resin layer is separated from the supporting substrate.
On the wiring layer formed on the supporting substrate, a plurality of semiconductor chips are normally mounted. The plural semiconductor chips are collectively resin-sealed, and thereby a resin-sealed body is manufactured. The wiring layer of the resin-sealed body is cut together with a sealing resin layer, and thereby the resin-sealed body is separated into circuit structure bodies (semiconductor devices). The resin-sealed body having the plural semiconductor chips is required to suppress warpage when separating from the supporting substrate. The warpage generated in the resin-sealed body is likely to remain in the circuit structure bodies into which the resin-sealed body is separated. The warpage generated in the circuit structure bodies (semiconductor devices) becomes a factor to reduce adhesiveness and connectivity when the circuit structure body is mounted on a substrate or the like.